Here's a subtle marble-like background for use on websites.
Source V. Hartikainen
Background formed from the original with an emboss effect
Source GDJ
Beautiful dark noise pattern with some dust and grunge.
Source Vincent Klaiber
Very dark pattern with some noise and 45-degree lines.
Source Stefan Aleksić
Prismatic Floral Pattern 3 Variation 3 No Background
Source GDJ
Subtle scratches on a light gray background.
Source Andrey Ovcharov
This is a grid, only it’s noisy. You know. Reminds you of those printed grids you draw on.
Source Vectorpile
Vector version of a png that was uploaded to Pixabay by pencilparker
Source Firkin
Prismatic Groovy Concentric Background
Source GDJ
Just to prove my point, here is a slightly modified dark version.
Source Atle Mo
Here I have tried to create something that would look like maple wood. Not sure how well it's turned out, but at least it looks like wood.
Source V. Hartikainen
From a design found in 'History of the Virginia Company of London; with letters to and from the first Colony, never before printed', Edward Neill, 1869.
Source Firkin
From a drawing in 'Gately's World's Progress', Charles Beale, 1886.
Source Firkin
You can never get enough of these tiny pixel patterns with sharp lines.
Source Designova
Looks like a technical drawing board: small squares forming a nice grid.
Source We Are Pixel8
Prismatic Triangular Background Design Mark II 5
Source GDJ
Background formed from the iconic plastic construction bricks that gave me endless hours of fun when I was a lad.
Source Firkin
Inspired by a drawing in 'Poems', James Smith, 1881.
Source Firkin
From an image on opengameart.org shared by rubberduck.
Source Firkin
Different from the original in being a simple tile stored as a pattern definition, rather than numerous repeated objects. Hence easy and quick to give this pattern to objects of different shapes. To get the tile in Inkscape, select the rectangle and use shift+alt+i.
Source Firkin
Abstract Tiled Background Extended 8
Source GDJ
This was formed by distorting an image of a background on Pixabay.
Source Firkin
Prismatic Groovy Concentric Background
Source GDJ